The Illness
by SophieRomanoff
Summary: When Natasha becomes gravely ill, it is a fight against time to figure out what is happening to her and why. Natasha fights for her life, but will the team be able to find the cause before it's too late? Come find out.
1. Chapter 1

/Hey everyone! Warnings throughout the fic for medical things some people may find upsetting; including lifesaving procedures etc. Please be careful but otherwise enjoy!/

Natasha had started to feel ill a few days ago.

To begin with, it had felt like the flu. Slight fever, sore throat, muscle aches. Nothing too worrying.

She'd gone about her usual routine at the tower; wake early, exercise, teach classes at the academy, come home, eat dinner, hang out with the others.

A few days into the illness, she'd had to cancel her classes and stay at the tower.

She was still sure it was the flu, but her chest was tighter by the hour, so exercising was out of the question.

The others all had their own lives and jobs, but Tony and Bruce would often leave the labs to come check on her. Bruce would make her tea and soup, Tony would make her laugh.

Then it had advanced into what Natasha presumed to be a stomach bug.

She holed up in her en-suite and puked her guts up for a few hours straight before finally being able to stand, brush her teeth, and collapse on the bed.

When she woke, she was drenched with sweat and Clint's arm was thrown over her waist.

Her heart pounded in her ears as she stood and slowly walked out her room and down to the kitchen.

It was past ten am, and the fact Clint was sleeping in told her it was Saturday.

She flicked the kettle on and leaned against the counter as she waited for it to boil.

She absently rubbed at her sternum, wincing at the pain that crept down her ribs and up her throat.

She coughed a couple times as she filled her mug, setting the kettle down.

A sleepy Clint appeared at the doorway, making a beeline for the coffee machine.

Natasha held her mug of cooling tea for the next five minutes, but didn't take a sip.

Tony looked up from the table, eyebrow raising. "You gonna stand there all day?"

Natasha blinked and shook her head.

Bruce, at his other side, frowned. "Natasha, are you still feeling ill?"

She didn't answer and Clint touched her back, eyes widening a little. "Christ, Tasha, you're burning-"

Her chest had been feeling tighter and tighter since the moment she woke up, but now it was reaching danger levels, not just 'I have a cold'.

"I-" the woman choked out, her eyes widening with panic as her back hit the kitchen side and her mug slid from her grip.

Clint grabbed her shoulders and quickly turned, shoving her into the first seat he could find.

"Tash?'' He bent, cupping her cheek.

"I...can't-" a rasping inhale sounded from her chest and her hand came up to touch her throat.

"Breathe-" she gasped.

Bruce was up in another second, pushing Clint's hand away so he could hold her head up, his other hand pressed to the inside of her wrist.

"Natasha, try to talk to me, what is it?"

"M...my chest. Can't...breathe-" her shoulders heaved with each frantic, rattling breath.

Her face drained of colour, lips tinged blue. Her eyelids fluttered as she fought for air.

Each breath sounded wet and gurgled and as Bruce carefully hit her back, Natasha coughed and retched violently.

Blood splattered over her lips and down Bruce's shirt.

Then her eyes were rolling back into her head and she went slack, tipping forward on the chair.

Bruce caught her. "The lab. Now." Clint reached for her, sliding the woman into his arms as Bruce rushed ahead to prep the lab with Tony.

Once there, Clint laid her down on the hospital bed, face streaked with blood.

"What's happening? What the hell is wrong with her?"

"I don't know." Bruce shook his head, placing his stethoscope in his ears, sliding the metal up the front of her shirt.

A couple of moments later, he was rushing to the equipment. "Her lungs are full of blood."

He quickly shoved gloves on, gathering the stuff he needed.

Just as he moved towards Natasha, she stilled and her chest fell. And stopped.

"Nat-" Clint choked.

"Tony, the intubation kit. Now." Bruce cut through the material of her shirt and pulled the sides away from her skin.

With no real warning, he stabbed a needle through Natasha's skin and through her ribs, pulling the plunger. The tube filled with red and brown liquid.

Bruce emptied the tube and did it again, this time it came out half full.

In mere moments, he had a thinner tube sliding into her body.

The tube connected to a container and soon the liquid trickled through.

One problem addressed, Bruce got her hooked up to a monitor, but still felt her neck for a pulse.

He felt a flutter under his fingertips, a flutter that told him if he didn't sort out her breathing in the next twenty seconds, she would arrest.

Tony handed Bruce the kit and Bruce pulled her jaw open, expertly winding the intubation tube down her throat.

In seconds, he had the tube connected to the ventilator, and her chest rose with a soft hiss.

The monitor told him that her heart rate was picking up, thready, but stable.

With Natasha out of immediate danger, they were onto the next problem.

What the hell was wrong with her?


	2. Chapter 2

/I'm by no means an expert about medical things but have done a ton of research and I think it's pretty accurate. Anyways, if anyone in an expert please don't be rude I tried my best! Enjoy!/

Bruce moved with efficiency for the next two hours.

The Shield med team was on their way, only half an hour out.

But they were still at a loss.

Routine blood tests came back murky and showed only the fact that she was deteriorating quickly.

The display of the monitors was hardly reassuring, with her blood pressure dropping constantly, and her heart rate erratic.

But she was alive. They had time. Not a lot of time, but some.

Bucky and Steve had come home from their run only minutes after Natasha had been taken to the lab.

They'd entered the kitchen to find broken glass and blood across the floor.

They'd followed the trail, Steve with his shield, Bucky with his gun.

Once at the lab, Steve had stopped for a moment before pushing the doors open.

"Talia-" Bucky had choked out, taking a step towards the bed.

"What happened?" Steve had demanded and Bruce had only shook his head.

"We don't know."

That's still where they were at, scattered around the tower, searching for something, anything.

Clint had torn their room apart, had collected everything she'd drank from and worn for the last two weeks.

Bucky and Steve had taken the kitchen, pulling her snacks and food from the shelves and placing them all in a box.

Tony was in the second lab, testing every single thing they brought him under the microscope.

Bruce had carefully examined nearly every part of Natasha's body, expecting to find some sort of lesion or cut or needle mark.

Anything that would explain this.

He wasn't sure it had been anything external, that it was poison or anything like that.

But this wasn't any normal illness, it couldn't be.

Something told Bruce this had been an attempt on Natasha's life, and he had to listen to that.

But still the tests came back clear, nothing in the drinks or the food, nothing in her room, nothing on her clothes.

Tony's voice came over the intercom. "Med team is landing, will be there in five. We still haven't found anything, Bruce, any other ideas?"

The man exhaled and shook his head. "We'll need to send someone to the academy, search her locker and the gym. Shut it down, just in case."

The others would be listening too. "Bucky, Steve, search the rest of the tower. Clint, come here."

Bruce turned back to Natasha, going through the motions of checking her vitals again.

Her fever had skyrocketed, and he added more meds to the IV.

Hopefully if nothing else, they could bring her fever down.

His hand brushed her hair from her face and he cursed.

The numbers didn't show the heat coming off her or the dry, red skin as he brushed her hair back.

He sighed and checked on the breathing tube, glancing back as Clint came in.

"Why did you need me?" The archer asked quietly, looking wrecked.

"Clint," Bruce said carefully, "I'm sure we will figure this out. But I think she needs you here more than she needs you tearing the place apart."

Clint dragged his fingers through his hair, nodding. "Yeah. Okay."

He pulled out the chair beside the bed and sat, taking her hand and pressing a kiss to it.

"I love you, Nat." He said quietly, voice shaking just a little.

They'd had their fair share of moments like this. But none quite as helpless.

Bruce moved to the corner to give them some space, as he double checked the blood results.

He heard Clint before he heard Natasha.

"Bruce-" a choked cry of his name.

Bruce turned, heart dropping as he rushed over.

Natasha was seizing, body arching off the bed and slamming down, her hands curled in front of her chest.

A grating noise sounded and Bruce pulled her onto her side. "Hold her." He told Clint, his own fingers nearly in her mouth as he held the breathing tube in place.

Pink foam bubbled at her lips as her body continued the agonizing jerking movements.

The medics had arrived, but they were certainly not in charge.

"Get me diazepam, now." Bruce demanded, helping Clint brace her on her side.

It was too long. It was going on too long.

"You." Bruce nodded his head at the medic closest to the door, "Tony is in the other lab. Get him. Tell him we need a brain scan. Go!" He growled, eyes flashing green.

The medic stumbled and nodded, eyes wide as he rushed from the room.

One of the team came forward, quickly sliding the needle into the flesh of her thigh.

As the seizure neared dangerously long levels, Natasha began to still.

Bruce exhaled, heart pounding as he rolled her onto her back and watched the monitors.

Her blood pressure had plummeted again.

But the chest drain had barely collected anything, so it wouldn't be down to internal bleeding.

On instinct, Bruce pulled back the lids of Natasha's eyes.

Bloodshot.

He tilted her head to the side, pulling her hair from her ear, cursing.

As he touched her ear, his fingers came back wet.

They were officially out of time for speculation and guesses.

They needed answers now.

Because there was fluid around her brain, and she was dying right in front of them.

They had less than a day.


	3. Chapter 3

In the last twenty minutes, Natasha had had a brain scan and whilst they had the machines ready, a chest scan since that was where some of the first symptoms had began.

Bruce only grew more frustrated as he looked at the results.

The brain scan was of no use; showed only the fact the fluid was surrounding her brain.

As he looked over the results, the med team was already implanting a shunt to drain the fluid.

But the x-ray didn't show a reason for the haemorrhage.

Then the chest results.

Pleural effusions, air space disease.

It all added up that something had been inhaled but what, he didn't have much of a clue.

He abandoned the scans and met Tony in the lab, bent over the microscopes cluttering the desk.

"Anything from the lung fluid?" Bruce leaned over his shoulder to see.

"If I knew what I was searching for, then I would probably find something. But I'm blind here, Bruce."

The man nodded, checking his watch.

"I'll contact the search teams. The x-rays are back, there's shadowing on her lungs so it's likely cause by inhalation of...something."

"Send a copy of the scans, I'll have a look." Tony murmured.

Bruce quickly sent the pictures and touched his phone to his ear.

First, he spoke to the remaining members of the team, still searching the tower.

They'd found nothing.

Bruce told them to wear the face masks and hung up.

Next, the team searching the academy.

They were just getting to her locker and Bruce stayed on the line to listen.

"We might have found something."

"Open the video, let me see." Bruce held the phone and watched as they pulled the items down.

Work out clothes, water bottle, shower stuff, and a box.

"What is that? Open it." Bruce anxiously sat, tapping his foot as they got the box open.

Letters. Lots of letters.

"Just fan mail." The agent sighed. "Should we bring the bottles in for testing?"

But something niggled at Bruce's head.

Ever since the New York battle they'd been receiving fan letters.

The doorman at the tower would often bring a big bag up to the team and they would collect their letters and drawings and presents.

But Natasha, as the only woman on the team, was very popular with the young girls and teenagers.

She had more letters than almost anyone.

The box in her locker was small.

Meaning that Natasha either kept only a slight amount of her letters and threw the rest or...or they weren't fan letters.

What if they were hate letters?

"Bring everything, the box included. Wear gloves and the masks."

Bruce sat back, ending the call and moving to his laptop.

He spent the next thirty minutes researching until the team came back from the academy.

He had an idea.

Now he had to test it.

He made sure Tony was wearing the right gear before following his gut.

He emptied the letters out and had Tony examine them whilst he went to the microscope with the sample of the fluid from her lungs.

Please.

Please be what I'm looking for.

Twenty minutes later, he had his answer.

Positive.

They'd figured it out.

Bruce laughed, slightly maniacally, standing to collect the right medications.

Through the intercom came six words.

"Natasha has gone into cardiac arrest."


	4. Chapter 4

"Shit." Bruce cursed. "Tony, I need the antibiotics and antitoxin ready in the next five minutes or this is going to have been for nothing."

Bruce ran to the next lab, not stopping to put on a mask; the way Natasha had contracted the illness meant it could not be passed on to another person.

He pushed through the door, the machines screeching around the room.

The medics were already administering CPR, the intubation tube had been disconnected from the machine and air was being given manually through an ambu bag.

Bruce told the man pressing against her chest to stop and Bruce took over immediately.

He counted in his head and spoke to the team.

"Make sure...her IV is in...Tony has the...medications-"

The medics carefully moved around him, one holding her head carefully so the compressions wouldn't knock the shunt they'd not long put in.

Another checked the IV in the back of her hand and as Tony barelled through the doors, he took the needles and expertly slid the liquid into the bag attached to the tubing.

He adjusted the flow and soon the meds were dripping into her vein.

But it wasn't an instant cure. It wasn't like one second she was dying and the next she was okay.

Her heart had stopped. Her organs had began to shut down.

Bruce shouted for someone to bring the defibrillator over and after attaching the pads to her chest, he called for them all to clear.

Natasha's body jolted and immediately Bruce was back hovering over, pushing down over her heart.

"Get me adrenaline. And a long needle."

It would take too long for the adrenaline to move around her body if they used the IV, he would have to inject it straight into the failing muscle inside her chest.

The team was good and in twenty seconds, one of the medics had the needle.

Bruce stopped for a second and the man guided the needle through her skin, through ribs, and straight into her heart.

He depressed the plunger until it was empty and then Bruce was compressing hard and fast once more.

The defibrillator beeped, they stepped back and another shock was delivered.

There was a quivering on the screen.

"Again. Clear."

Her body arched again and the quivering on the screen straightened into something more like a normal rhythm.

"How long was she coding for?" Bruce looked back.

"Three minutes." One of the men murmured and Bruce nodded, peeking back her eyelids and checking with his penlight.

Her eyes responded and he nearly cried with relief.

They'd gotten her back in time.

"Get her back on the machine." Bruce ordered, looking back at Tony, who was pressed against the wall, looking a little terrified.

"Tony, we're gonna need another scan. A full body one, to check her organs."

The man nodded, swallowing.

Before leaving, he knelt next to Clint, who had been sitting in the corner of the room, shuddering and crying, looking about ready to pass out.

"Barton? Clint, come on bud, up we get." Tony murmured, lifting him under his armpits.

"Let's go sit down, yeah?" Tony handed Clint over to Bruce, who helped the archer into a seat, pressing a hand to the nape of his neck.

"Deep breaths, Clint." Bruce said softly.

Tony backed up and headed to his lab. She wasn't well enough to be moved so he would have to carry the portable scanner over to where she was.

Bucky and Steve were waiting for him, sitting close to each other and looking stricken.

"Bruce got her back." Tony said quietly. "We found...we found out what's wrong with her. Someone went to great lengths to try and ensure Natasha's death. Whilst we wait for the meds, you two need to find who did this." Tony grabbed the machine and dragged it to the door.

"Start with the letters and for gods sake, use the face masks and gloves."

"Tony, what is it?" Steve looked up from the box, wrapped in protective material with a giant warning sign across it.

"Anthrax. Someone tried to kill her with anthrax."


	5. Chapter 5

It had taken less than an hour to comb through the letters from Natasha's box. Not a lot of people felt so strongly about the woman that they would go through the effort to send hate mail.

They'd matched the handwriting on three of the letters.

The rest had been a whole lot of men angry that a woman could kick their asses, or were crude remarks about her figure and/or ability to do a 'mans' job.

Empty threats sent by insecure men in basements.

The other three had been different.

The handwriting had been decidedly female compared to the other letters, and the words had flowed in half-finished sentences that sometimes didn't make a whole lot of sense.

The gist of it was basically one large rambling warning for Natasha.

That she would 'get what was coming to her' and that she would 'pay for what she had done'.

Steve and Bucky exchanged glances before nodding and sealing the three letters in clear plastic bags, standing up to either deliver the letters to Tony in the lab or to talk to Shield.

They didn't have much to go on.

The woman had left no name and the paper was just plain and pulled from a generic notebook.

Not that they'd been expecting something as useful as hotel stationary but _something_ would have been nice.

But after a brief call to Shield, Maria assured Steve that they could scan the handwriting in and see if it matched anything on their databases and if not, they could extend their search to other agencies.

Steve made sure Tony knew to send the photos to Hill ASAP and headed down to the med room to sit and begin their wait.

…

Almost ten hours passed before they had any news.

Natasha wasn't getting _better_ per se but Bruce assured them that the fact she wasn't getting worse was somewhat of a good sign.

The Shield team had finally gotten a hit on the handwriting; it hadn't come from their files but they'd also sent out copies to multiple business' and establishments until they'd found something.

The writing matched case notes at a doctors' office downtown, belonging to one Rosa Swan MD.

They'd sent a team and had brought her into Shield immediately.

It hadn't been hard to get a confession out of the woman; she had been sure that Natasha would already be dead and that she had done what she had set out to do.

In fact, she was practically gloating in the faces of the agents Shield sent in; Maria Hill had insisted it be her a long with two much bigger agents should the woman see fit to try and escape (not that Hill couldn't have taken her, but back up was always a good call).

She didn't try to escape and seemed relatively calm about the whole thing considering she'd not thought she would get caught.

The woman had never actually even seen Natasha in person but held her responsible for the death of her husband.

He'd died during a battle The Avengers and Shield had had months previous.

He'd been a police officer and had helped clear the streets during the start of the fight, but along the way had gotten caught up in the whole mess.

When she'd searched for information about his death, the only details not redacted were the location of where he had been found and the person he had last been seen with; Agent Natasha Romanoff of SHIELD.

Instead of grieving, she had devised a plan that would draw out Natasha's pain to match her own.

First the two letters, spread months apart, made to rattler her.

To get Natasha to look over her shoulder and be fearful of what was to come.

To scare the woman, to make her suffer.

To make her scared for her life.

Next, the letter sent to kill; received only a week earlier and that unfolded to reveal a lethal amount of anthrax.

Inhaled or spread now across a single a page, a half empty box and a small chunk of floor where Natasha had stood to open the letter.

Sent far from home, supposed to be untraceable.

She had been shocked when the Shield swat team had crashed into her office.

She thought she'd been smarter but Shield and The Avengers had been smarter still.

She was being held indefinitely at a Shield facility where she would face charges or would rather just…disappear should Natasha not survive.

Clint had taken the news with mixed emotions; anger, sorrow, more anger, confusion, helplessness, relief at having found the woman who tried to murder his girlfriend.

The archer recognised the womans' husband as he scanned through the un-redacted file.

It stated that Agent Romanoff had risked her own life to save his; had fought valiantly to try and keep him alive but that he had died of his wounds before Natasha had had a chance to try and call for help.

A couple of black boxes covering text had been the difference between life and near death.

….

A week passed and Natasha had made no signs of waking up.

But her vitals grew stronger every day and the organs that had begun to fail seemed to be improving a little too.

She was still nowhere near well but the chest drain had been able to come out into the third day and the brain shunt carefully removed into the fifth as the swelling began to subside and the fluid stopped collecting.

The anti-toxin and antibiotics still filtered into her body every hour on the hour, as well as nutrients and glucose to give her body what it needed until she would wake.

And she would wake, Bruce had grown certain of that during the first day and knew it now even more.

But that didn't mean the wait wasn't agonising and still terrifying to the team.

The members crowded the hospital room daily and Natasha was never left on her own.

They had conversations, talked to Natasha instead of at her, played her favourite music.

Clint slept carefully curled in a camp bed that had been set up next to Natasha's, hand in hand until he woke in the morning.

He ran his fingers gently through the red hair that remained; some had been shaved to make way for the shunt.

He wiped down her face, arms and legs with a wet cloth every morning and night.

The others were also a near constant in the room, for which Clint was grateful.

Being left alone with his thoughts had never served him well.

Soon Natasha's fever had abated some and whilst still a little high, was nowhere near life threatening anymore.

She still couldn't breathe on her own but Bruce was confident that when she woke up, she would be able to have it removed.

Things were looking up, but still she slept.

It was understandable; she had almost died numerous times and her body needed to conserve all its energy into healing itself.

A week turned into ten days and things were brighter still.

Her temperature back to normal levels, the anti-toxins being weaned down until she didn't need that either.

On the eleventh day, Natasha opened her eyes.

And finally it was like the team could breathe again.


	6. Chapter 6

Hey guys! Enjoy the epilogue. I hope you all liked this! Leave a comment for me if you did? Let me know if you'd like a more detailed epilogue of full recovery, cause I can probably do that

/ / /

The next few days were by no means easy.

The first time Natasha woke up, she stayed awake for less than a minute before her eyes slipped shut again.

It had been only thirty seconds, but everyone was over the moon.

Clint's cheeks were wet with tears as everyone hugged, grinning and laughing in that relieved, slightly hysterical way.

Bruce assured them that the woman falling asleep so quickly was nothing but a good sign. She'd opened her eyes and they'd even moved around the room a little.

Tony asked whether her seemingly not noticing the tube down her throat was a bad sign and Bruce carefully explained that Natasha had probably been so exhausted that it hadn't registered. He was sure when she next woke and was more with it, she would realise and they'd be able to remove it.

Clint and Bruce stayed as the others dispersed, not wanting to crowd her, but staying close enough to the med room that they could be there quickly.

Bruce hugged Clint, rubbing a hand up his back. "Things are looking good, Clint." He said softly. "Really good."

...

As Bruce had predicted, Natasha did indeed wake up somewhat more coherent.

Clint was abjectly terrified as the woman struggled, hands coming up to claw at the tube. He rushed over, gently tugging her hands from her face. "Shh, Nat, you're okay. We'll get it out okay? Just keep calm."

"Hey, Tash, just keep still and I'll get the tube out okay? I need you to relax, you might want to cough or feel sick, that's okay." Bruce had already gotten the oxygen mask ready for straight after.

He carefully detached the tube from the machine. "Just breathe through your nose, it's going to be uncomfortable." With a firm grasp on the tube, he pulled it quickly but gently until the end slid out of Natasha's mouth.

The woman shuddered, eyes watering as she coughed violently, inhaling raggedly.

"Deep breaths, I know it hurts, just stay calm and take slow breaths." Bruce murmured, hooking the oxygen mask over her mouth and nose, easing her back against the mountain of cushions.

Clint swallowed hard, light fingers brushing over Natasha's hair and down her cheek. "Take it easy, Talia, you're okay."

Eyes squeezed shut and as tense as anything, Natasha pulled in grating breaths, wincing as the air moved down her raw throat.

"You're doing so good," Clint murmured, his other hand sliding into Natasha's, "nice and slow, babe."

...

The next couple of hours consisted of Natasha sleeping on and off and going through numerous tests to test both her mind and body.

Somehow, incredibly, Natasha's mind appeared to be unaffected, even after the seizures, fluid build up and lack of oxygen at times.

She could hold a conversation, could remember things from her past, knew the answers to the questions Bruce asked.

The only thing she seemed to be having trouble with was choosing the correct word, sometimes using the wrong one for what she was trying to say, or just not being able to come up any word at all.

Bruce was a little worried about that, but hoped that once some of the exhaustion tapered back, Natasha would be able to speak completely clearly.

So it was worrying, but considering how badly her brain could have been damaged by the whole ordeal, they were taking that as a win.

As far as the physical tests went, Natasha also passed most of those. Her reflexes were a little slow but still fully present and she could move every part of her body.

She was suffering quite a lot with weakness at that stage; needing help to sit up or hold anything. Another thing that Bruce hoped would fade, with physical therapy and time, he was pretty certain Natasha would be back to usual self in about a month. In that respect anyways.

He had no doubt that there would be bouts of chronic fatigue and pain, as well as developing coughs and the flu more often than was normal and there was still the chance that memory problems could occur, especially in the short term. But, things were looking pretty good, especially considering just how sick the woman had been.

Natasha would be off work for a good couple of months whilst they worked to get her back to the best health she could be in, but she was just beyond grateful to be alive at that point.

She could scarcely believe that she'd been unconscious for so long, and had come so close to death so many times in such a short amount of time.

The realisation that she'd nearly died because of a misunderstanding should have shocked her, but instead, when Clint told her what had happened, she laughed.

She told him that they'd almost died for less, and that considering how their lives seemed to go, it wasn't really surprising.

...

The first night after waking, Clint finally got to sleep in the same bed as Natasha, with no fears of pulling out wires or hurting her.

She settled into his arms as the archer told her story and just before she dropped off, he told her how worried everyone had been and that how glad they were that she was still with them.

Clint promised that the next day would be filled with visits and hugs and tears and probably presents.

But for that night, it was just the two of them, Clint holding Natasha tight, whispering softly the words he'd been too scared to utter should they have sounded like a goodbye.

"I love you."


End file.
